Technical Abstract:
Field studies were conducted in 2003 and 2004 to determine the effects of alternate grassy weed hosts, post-emergence grass control, MON863 containing glyphosate herbicide tolerance on the western corn rootworm, Diabrotica virgifera virgifera LeConte. The experimental design was factorial randomized complete block split-split-plot. Main plots consisted of MON863, its isoline and isoline plus tefluthrin. The sub-plots consisted of two weed species giant foxtail and large crabgrass, and sub-sub-plots consisted of weed removal at V3, V4, in 2003: V5, V6 in 2004, no weed removal, and weed free plots. Insect management tactics significantly affected the total number of beetles that emerged from all the treatments in both years. The isoline had highest number of beetles and lowest was from MON863 alone. Significantly more beetles emerged from MON863 plus grassy weeds than in MON863 alone in some specific combinations in 2003. Adult production was skewed towards the females in both years. Root damage was significantly affected by insect management tactics in both years. MON863 offered the best protection to the roots. Weeds and weed removals did not significantly affect damage to MON863 in either year.